In the twentieth century divorce became possible and then became more and more common. Usually the children in a divorce stay with one parent and the other parent moves away. Child support is a way for the state to make certain that the parent who moves away supports his or her children to some extent.

If the parents were still living together, they would spend more on the children or less depending upon raises in salary or the loss of a job. The court (in Arizona, and in most other states) will also raise or lower child support depending upon the how much each of the parents earn.

Society is so very concerned about the child being supported properly that even if the parents try to agree in their divorce decree on a set amount of child support, the court may not approve this agreement. The court will very likely change child support even if the parents agreed not to, if one of them proves to the court at a later date that changing child support would be in the best interest of the minor children.

Child support is not meant to punish one parent or to reward the other. It is only to ensure that the parent who has the most responsibility for supporting the children is given some help by the other.

If the parents spend an equal amount of time with the children, and are responsible for an equal amount of the cost to raise them, (e.g. one child lives with each parent, or they alternate weeks at each parent's house) then the court may very well order no child support to be paid at all.